A step in the manufacture of metal cans involves cutting sheet metal strips. Can components, including tops and bottoms, are then formed from the metal strips. Machines of known construction, such as those manufactured by F. J. Littell Machine Co., assignee of the present invention, are utilized to convert coils of tin plate, alumium or tin-free steel or the like into strips.
The strips from which the can tops and bottoms are formed are known as straight cut or "scroll" cut strips. The term "scroll" comes from the irregular edge configuration cut into strips in one process as they are sheared to assure maximum metal utilization in each strip as the can tops or bottoms are punched from the strip by a punch press.
In the production process, the strips must be inverted before they are stacked on pallets for transport to the can-forming lines. As each strip is cut it is ejected from the cutting operation lying on one side. The can top forming machinery, because of characteristics of the finished product desired, must receive each strip in inverted relationship, i.e., with the strip lying on its other side. A strip inverter is conventionally employed in the context of a larger strip stacker to flip each strip from one side onto its other side before it is stacked on a pallet, for example, for ultimate delivery to the can forming operation.
As with virtually any production process, the speed at which strips can be fabricated, inverted and stacked affects the cost of the strip. It has been the experience of the F. J. Littell Machine Co. that the strip inverting process is the limiting factor. With known strip inverting apparatus a maximum of approximately one hundred strips can be inverted per minute.